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1
.gitattributes vendored
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@ -1 +0,0 @@
* text=auto

1
.gitignore vendored
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@ -0,0 +1 @@
TODO

64
ChangeLog
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@ -1,65 +1,11 @@
checkmail 0.7 (unreleased)
* Re-format ChangeLog.
* Update POD documentation (repository, issue tracker).
* Add README.
* Change mail address.
* Fix display of CNAME/A records in log file.
checkmail 0.6.2 (2016-01-09)
* Try to handle CNAMEs and resolve them to A records.
Change documentation accordingly.
Fixes #55.
* Allow setting an empty envelope-from ('<>') using '-s'.
Change documentation accordingly.
Update version and copyright dates.
Fixes #54.
checkmail 0.6.1 (2011-12-04)
* Fix annoying error message (and some small changes).
checkmail 0.6 (2011-10-24)
* Don't temp-fail on random address check.
* Fix regexp for syntax check.
checkmail 0.5
* Add syntax check for mail addresses.
Change documentation accordingly.
Fixes #11.
checkmail 0.4
* Add overrides for configuration (MAIL FROM/EHLO).
New commandline options: -s <sender> and -e <EHLO>.
Change documentation accordingly.
* Replace splitaddress() by Mail::Address.
* -r: Create a really random localpart.
Add create_rand_addr().
* Analyze failure codes, don't fail on temporary failures.
Add analyze_smtp_reply().
Fixes #8.
checkmail 0.3
Version 0.3
* Add Changelog.
Thomas Hochstein <thh@inter.net> 2010-06-16 22:48:23 +0200
* Add documentation in POD format.
- Drop checkmail.readme
Thomas Hochstein <thh@inter.net> 2010-06-16 21:11:43 +0200
* Complete rewrite.
- use strict;
@ -72,8 +18,10 @@ checkmail 0.3
- batch processing: set exit status to highest generated value
Fixes #9.
Fixes #10.
Thomas Hochstein <thh@inter.net> 2010-06-16 21:11:23 +0200
checkmail 0.2
Version 0.2
* Initial check-in.
Thomas Hochstein <thh@inter.net> Wed Aug 8 22:00:00 2010 +0200

13
README.md
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@ -1,13 +0,0 @@
# checkmail
## Description
**checkmail** determines the mail server (or servers) responsible for the domain of the mail address (MXes); if none are available, it falls back on the host with the corresponding name (if available). It then establishes an SMTP connection and goes through the SMTP dialogue until just before an email is actually sent and checks whether mail to the recipient address would be accepted in principle. If desired, checkmail can also test sending to an address that is certainly invalid in order to check whether the replies from the recipient mail server are reliable at all or whether every recipient address is accepted (initially).
The sender of the apparent test email and the HELO parameter to be used can be configured in the script or passed as a parameter during the call.
Additional options can be used to check several addresses present in a text file, to display the complete SMTP dialogue or to force a connection to a specific mail server (instead of checking the relevant MXes).
## More information
Please see the [distribution page](https://th-h.de/net/software/checkmail/) (in German).

7
TODO
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checkmail To-Do-Liste
=====================
* better analyze SMTP response codes

169
checkmail.pl
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@ -1,15 +1,15 @@
#! /usr/bin/perl -w
#! /usr/bin/perl -W
#
# checkmail
# checkmail Version 0.3 by Thomas Hochstein
#
# This script tries to verify the deliverability of (a) mail address(es).
#
# Copyright (c) 2002-2016 Thomas Hochstein <thh@thh.name>
# Copyright (c) 2002-2010 Thomas Hochstein <thh@inter.net>
#
# It can be redistributed and/or modified under the same terms under
# which Perl itself is published.
our $VERSION = "0.7 (unreleased)";
our $VERSION = "0.3";
################################# Configuration ################################
# Please fill in a working configuration!
@ -17,14 +17,15 @@ my %config=(
# value used for HELO/EHLO - a valid hostname you own
helo => 'testhost.domain.example',
# value used for MAIL FROM: - a valid address under your control
from => 'mailtest@testhost.domain.example'
from => 'mailtest@testhost.domain.example',
# a syntactically valid "random" - reliably not existing - localpart
rand => 'ZOq62fow1i'
);
################################### Modules ####################################
use strict;
use File::Basename;
use Getopt::Std;
use Mail::Address;
use Net::DNS;
use Net::SMTP;
@ -35,11 +36,11 @@ my $myself = basename($0);
# read commandline options
my %options;
getopts('Vhqlrf:m:s:e:', \%options);
getopts('Vhqlrf:m:', \%options);
# -V: display version
if ($options{'V'}) {
print "$myself v $VERSION\nCopyright (c) 2002-2016 Thomas Hochstein <thh\@thh.name>\n";
print "$myself v $VERSION\nCopyright (c) 2010 Thomas Hochstein <thh\@inter.net>\n";
print "This program is free software; you may redistribute it and/or modify it under the same terms as Perl itself.\n";
exit(100);
};
@ -52,24 +53,18 @@ if ($options{'h'}) {
# display usage information if neither -f nor an address are present
if (!$options{'f'} and !$ARGV[0]) {
print "Usage: $myself [-hqlr] [-m <host>] [-s <from>] [-e <EHLO>] <address>|-f <file>\n";
print "Usage: $myself [-hqlr] [-m <host>] <address>|-f <file>\n";
print "Options: -V display copyright and version\n";
print " -h show documentation\n";
print " -q quiet (no output, just exit with 0/1/2/3)\n";
print " -l extended logging\n";
print " -r test random address to verify verification\n";
print " -m <host> no DNS lookup, just test this host\n";
print " -s <from> override configured value for MAIL FROM\n";
print " -e <EHLO> override configured value for EHLO\n";
print " <address> mail address to check\n\n";
print " -f <file> parse file (one address per line)\n";
exit(100);
};
# -s / -e: override configuration
$config{'from'} = $options{'s'} if defined($options{'s'});
$config{'helo'} = $options{'e'} if $options{'e'};
# -f: open file and read addresses to @adresses
my @addresses;
if ($options{'f'}) {
@ -92,14 +87,7 @@ if ($options{'f'}) {
my (%targets,$curstat,$status,$log,$message);
foreach (@addresses) {
my $address = $_;
# regexp taken from http://www.regular-expressions.info/email.html
# with escaping of "/" added two times and "*" changed to "+"
# in localpart, second alternative
if ($address !~ /^(?:[a-z0-9!#$%&'*+\/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+\/=?^_`{|}~-]+)*|"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f]+)")@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?$/i) {
printf(" > Address <%s> is syntactically INVALID.\n",$address) if !($options{'q'});
$curstat = 2;
} else {
my $domain = Mail::Address->new('',$address)->host;
(undef,my $domain) = splitaddress($address);
printf(" * Testing %s ...\n",$address) if !($options{'q'});
$log .= "\n===== BEGIN $address =====\n";
# get list of target hosts or take host forced via -m
@ -121,7 +109,6 @@ foreach (@addresses) {
$log .= $message . '.';
};
$log .= "====== END $address ======\n";
};
$status = $curstat if (!defined($status) or $curstat > $status);
};
@ -154,20 +141,11 @@ sub gettargets {
# no MX record found; log and try A record(s)
} else {
print_dns_result($domain,'MX',undef,$resolver->errorstring,$logr);
print(" Falling back to A record(s) ...\n") if !($options{'q'});
print(" Falling back to A record ...\n") if !($options{'q'});
# get A record(s)
# may get CNAMEs instead ...
if (my $query = $resolver->query($domain,'A','IN')) {
print_dns_result($domain,'A/CNAME',$query->header->ancount,undef,$logr);
print_dns_result($domain,'A',$query->header->ancount,undef,$logr);
foreach my $rr ($query->answer) {
if ($rr->type ne 'A') {
# report CNAMEs and don't add them to target list
if ($rr->type eq 'CNAME') {
printf (" ~ '%s' is a CNAME for '%s' and will be resolved accordingly. \n",$rr->name,$rr->cname) if !($options{'q'});
$$logr .= sprintf("- CNAME resolved: %s -> %s\n",$rr->name,$rr->cname);
}
next;
}
$targets{$rr->address} = 0;
$$logr .= sprintf("- %s\n",$rr->address);
};
@ -224,22 +202,20 @@ sub checksmtp {
my ($success,$code,@message) = try_rcpt_to(\$smtp,$address,$logr);
# connection failure?
if ($success < 0) {
$status = connection_failed(@message);
$status = connection_failed();
# delivery attempt was successful?
} elsif ($success) {
# -r: try random address (which should be guaranteed to be invalid)
if ($options{'r'}) {
my ($success,$code,@message) = try_rcpt_to(\$smtp,create_rand_addr(Mail::Address->new('',$address)->host),$logr);
(undef,my $domain) = splitaddress($address);
my ($success,$code,@message) = try_rcpt_to(\$smtp,$config{'rand'}.'@'.$domain,$logr);
# connection failure?
if ($success < 0) {
$status = connection_failed(@message);
# reset status - the address has been checked and _is_ valid!
$status = 3;
print " > Address verification currently impossible. You'll have to try again or send a test mail ...\n" if !($options{'q'});
$status = connection_failed();
# verification impossible?
} elsif ($success) {
$status = 3;
print " > Address verification impossible. You'll have to send a test mail ...\n" if !($options{'q'});
print " > Address verificaton impossible. You'll have to send a test mail ...\n" if !($options{'q'});
}
}
# if -r is not set or status was not set to 3: valid address
@ -265,18 +241,16 @@ sub checksmtp {
return $status;
}
############################### create_rand_addr ###############################
# create a random mail address
# IN : $domain: the domain part
# OUT: $address: the address
sub create_rand_addr {
my($domain)=@_;
my $allowed = 'ABCDEFGHJKLMNPQRSTUVWXYZabcdefghjkmnpqrstuvwxyz23456789-+_=';
my $address = '';
while (length($address) < 15) {
$address .= substr($allowed, (int(rand(length($allowed)))),1);
};
return ($address.'@'.$domain);
################################# splitaddress #################################
# split mail address into local and domain part
# IN : $address: a mail address
# OUT: $local : local part
# $domain: domain part
sub splitaddress {
my($address)=@_;
(my $lp = $address) =~ s/^([^@]+)@.*/$1/;
(my $domain = $address) =~ s/[^@]+\@(\S*)$/$1/;
return ($lp,$domain);
};
################################ parse_dns_reply ###############################
@ -324,18 +298,16 @@ sub print_dns_result {
# IN : \$smtp : a reference to an SMTP object
# $recipient: a mail address
# \$log : reference to the log (to be printed out via -l)
# OUT: $success: exit code (0 for false, 1 for true, -1 for tempfail)
# OUT: $success: true or false
# $code : SMTP status code
# $message: SMTP status message
# \$log will be changed
sub try_rcpt_to {
my($smtpr,$recipient,$logr)=@_;
$$logr .= sprintf("RCPT TO:<%s>\n",$recipient);
my $success;
$$smtpr->to($recipient);
my $success = $$smtpr->to($recipient);
if ($$smtpr->code) {
log_smtp_reply($logr,$$smtpr->code,$$smtpr->message);
$success = analyze_smtp_reply($$smtpr->code,$$smtpr->message);
} else {
$success = -1;
$$logr .= "---Connection failure---\n";
@ -356,32 +328,11 @@ sub log_smtp_reply {
return;
}
############################### analyze_smtp_reply ##############################
# analyze SMTP response codes and messages
# IN : $code : SMTP status code
# @message : SMTP status message
# OUT: exit code (0 for false, 1 for true, -1 for tempfail)
sub analyze_smtp_reply {
my($code,@message)=@_;
my $type = substr($code, 0, 1);
if ($type == 2) {
return 1;
} elsif ($type == 5) {
return 0;
} elsif ($type == 4) {
return -1;
};
return -1;
}
############################## connection_failed ###############################
# print failure message and return status 1
# IN : @message : SMTP status message
# OUT: 1
sub connection_failed {
my(@message)=@_;
print " ! Connection failed or other temporary failure.\n" if !($options{'q'});
printf(" %s\n",join(' ',@message)) if @message;
print " > Connection failure.\n" if !($options{'q'});
return 1;
}
@ -395,7 +346,7 @@ checkmail - check deliverability of a mail address
=head1 SYNOPSIS
B<checkmail> [B<-Vhqlr>] [B<-m> I<host>] [-s I<sender>] [-e I<EHLO>] I<address>|B<-f> I<file>
B<checkmail> [B<-Vhqlr>] [B<-m> I<host>] I<address>|B<-f> I<file>
=head1 REQUIREMENTS
@ -415,10 +366,6 @@ Getopt::Std
=item -
Mail::Address I<(CPAN)>
=item -
Net::DNS I<(CPAN)>
=item -
@ -449,33 +396,32 @@ The hostname to be used for I<HELO> or I<EHLO> in the SMTP dialog.
=item B<$config{'from'}>
The sender address to be used for I<MAIL FROM> while testing.
May be empty ('') to set '<>' as MAIL FROM.
=item B<$config{'rand'}>
A "random" local part to construct a reliably invalid address for use
with the B<-r> option.
=back
You may override that configuration by using the B<-e> and B<-s>
command line options.
=head2 Usage
After configuring the script you may run your first test with
checkmail user@example.org
B<checkmail> will check the address for syntactic validity. If the
address is valid, it will try to determine the mail exchanger(s) (MX)
B<checkmail> will try to determine the mail exchanger(s) (MX)
responsible for I<example.org> by querying the DNS for the respective
MX records and then try to connect via SMTP (on port 25) to each of
them in order of precedence (if necessary). It will run through the
SMTP dialog until just before the I<DATA> stage, i.e. doing I<EHLO>,
I<MAIL FROM> and I<RCPT TO>. If no MX is defined, B<checkmail> will
fall back to the I<example.org> host itself, provided there is at
least one A record defined in the DNS. CNAMEs will be accepted and
resolved here. If there are neither MX nor A records for
I<example.org>, mail is not deliverable and B<checkmail> will fail
accordingly. If no host can be reached, B<checkmail> will fail,
too. Finally B<checkmail> will fail if mail to the given recipient
is not accepted by the respective host.
least one A record defined in the DNS. If there are neither MX nor A
records for I<example.org>, mail is not deliverable and B<checkmail>
will fail accordingly. If no host can be reached, B<checkmail> will
fail, too. Finally B<checkmail> will fail if mail to the given
recipient is not accepted by the respective host.
If B<checkmail> fails, you'll not be able to deliver mail to that
address - at least not using the configured sender address and from
@ -537,9 +483,6 @@ B<Please note:> You shouldn't try to validate addresses while working
from a dial-up or blacklisted host. If in doubt, use the B<-l> option
to have a closer look on the SMTP dialog yourself.
B<Please note:> To avoid shell expansion on addresses you submit to
B<checkmail>, use B<batch processing>.
=head1 OPTIONS
=over 3
@ -562,8 +505,8 @@ Log and print out the whole SMTP dialog.
=item B<-r> (random address)
Also try a reliably invalid address to catch hosts that try undermine
address verification.
Also try a reliably invalid address - defined in B<$config{'rand'}> -
to catch hosts that try undermine address verification.
=item B<-m> I<host> (MX to use)
@ -572,14 +515,6 @@ particular host irrespective of DNS entries. For example:
checkmail -m test.host.example user@domain.example
=item B<-s> I<sender> (value for MAIL FROM)
Override configuration and use I<sender> for MAIL FROM.
=item B<-e> I<EHLO> (value for EHLO)
Override configuration and use I<EHLO> for EHLO.
=item B<-f> I<file> (file)
Process all addresses from I<file> (one on each line).
@ -611,23 +546,25 @@ The script itself.
=head1 BUGS
Please report any bugs or feature request to the author or use the
bug tracker at L<https://code.virtcomm.de/thh/checkmail/issues>!
bug tracker at L<http://bugs.th-h.de/>!
=head1 SEE ALSO
L<https://th-h.de/net/software/checkmail/> will have the current
L<http://th-h.de/download/scripts.php> will have the current
version of this program.
This program is maintained using the Git version control system at
L<https://code.virtcomm.de/thh/checkmail>.
This program is maintained using the Git version control system. You
may clone L<git://code.th-h.de/mail/checkmail.git> to check out the
current development tree or browse it on the web via
L<http://code.th-h.de/?p=mail/checkmail.git>.
=head1 AUTHOR
Thomas Hochstein <thh@thh.name>
Thomas Hochstein <thh@inter.net>
=head1 COPYRIGHT AND LICENSE
Copyright (c) 2002-2016 Thomas Hochstein <thh@thh.name>
Copyright (c) 2002-2010 Thomas Hochstein <thh@inter.net>
This program is free software; you may redistribute it and/or modify it
under the same terms as Perl itself.